Question 113784
Suppose that N=the square root of x plus 3 models the number of cases of an infection, in millions, of a disease x years from now.
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Your formula could be either N(x) = sqrt(x)+3 or it could be
N(x) = sqrt(x+3)
I'm going to guess that it is the latter.
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a)Approximately how many cases of the infection will there be 9 years from now?
N(9) = sqrt(9+3) = sqrt(12) = 2sqrt3 million
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 b)In approximately how many years will there be 5 million cases.
5 = sqrt(x+3)
Square both sides to get:
25 = x+3
x = 22 years (You will have 5 million cases in 22 years)
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Cheers,
Stan H. 
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